Safety device for preventing overcharging of battery

Abstract

A safety device for preventing overcharging of a battery includes: a battery stack including a plurality of cells; a safety circuit connected to two or more cells and provided with an electrical conduction control unit that controls electrical conduction; and a closed circuit disposed between the cells connected to the safety circuit and provided with a switching unit which is switched on or off upon cell swelling, such that when cell swelling occurs, the switching unit is switched on by a pressing force, disabling the electrical conduction control unit of the safety circuit so electrical conduction between the cells is established via the switching unit, and when cell swelling occurs again, the switching unit is switched off, cutting off the electrical conduction between the cells.

Description

CROSS-REFERENCE(S) TO RELATED APPLICATION[0001]The present application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application Number 10-2013-0162225 filed on Dec. 24, 2013, which is incorporated by reference herein in its entirety.BACKGROUND[0002](a) Field of the Invention The present invention relates to a safety device for preventing overcharging of a battery, in particular, to a safety device which can prevent safety accidents attributable to overcharging of a battery by interrupting supply of electricity to a battery stack.[0003](b) Description of the Related Art[0004]Recently, in order to prevent environmental pollution caused by use of fossil fuels, environmentally-friendly vehicles which run on electricity, such as a hybrid vehicle, are in greater demand.[0005]An environmentally-friendly vehicle typically uses a battery which stores electric energy. The battery needs to have a high storage capacity so that the vehicle can run on electricity. Accordingly, medi...

AI Technical Summary

Benefits of technology

The present invention relates to a safety device for a battery that prevents overcharging. The device can detect when a battery cell swells due to overcharging and disconnect the charging circuit to ensure safety. This prevents damage to the battery and increases the energy density per unit volume of the battery system. This results in improved marketability of vehicles that use the safety device.

Problems solved by technology

However, it is difficult to install a medium or high capacity battery in a vehicle because medium or high capacity batteries often are large and heavy.

The battery structure using the pouch has high electric efficiency but low stability.

When the battery using such a battery pack is overcharged, the battery undergoes overheating, a voltage rise, and swelling in which the battery is inflated due to gas generated.

When the cell swelling does not reach a sufficient level before the thermal runaway occurs, even though this mechanism starts operating at the same time as the occurrence of thermal runaway, explosion of a battery may occur due to thermal runaway.

When the amount of gas generated is not sufficient, the cell tap may not be fractured.

However, a technology which interrupts supply of power to the relay cannot block the flow of current when the relay is short-circuited.

In an emergency such as an accident, the active-type overcharging-preventing safety structure is difficult to secure safety when electrical / electronic components are out of order, for example, when a sensor or a switch malfunctions.

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